Most coating agents applied to vehicle interior materials such as car seats, floor mats and ceiling members in the prior art are halogenated flame retardants such as decabromodiphenyl ether for imparting flame retardance. The recent concern about the environment demands to replace conventional halogenated flame retardants by non-halogen flame retardants. The non-halogen flame retardants, however, have drawbacks of poor flame retardance and poor water resistance, as compared with the halogenated flame retardants.
To overcome these problems, an attempt was made to encapsulate a water-soluble non-halogen flame retardant such as ammonium polyphosphate with a coating agent. JP-A 9-13037 discloses such a coating agent comprising a polyamide resin, acrylic resin or styrene resin although the resulting flame retardant is still less resistant to water.
JP-A 10-110083 and JP-A 2003-171878 disclose that ammonium polyphosphate particles can be admixed with acrylic emulsions in a stable manner when they are surface coated with melamine resins or the like. The emulsion compatibility is improved. However, if the coating agent has a low degree of curing, coatings applied and dried to substrates, typically fabrics are not improved in water resistance. For example, a problem has been pointed out that the coating surface becomes slimy when contacted with water. On the other hand, if the coating agent has a higher degree of curing, the above problem is overcome, but formaldehyde is detectable, raising an environmental problem.
In addition to the ammonium polyphosphate, the known non-halogen flame retardants include metal hydroxides such as aluminum hydroxide and magnesium hydroxide and phosphate esters, which are considered less flame retardant than the halogenated flame retardants.
There exists a need for coating compositions comprising non-halogen flame retardants having physical properties comparable to coating compositions comprising conventional halogenated flame retardants.